This invention relates to gas generators for catalytically reacting liquid, hydrocarbon containing fuel to be evaporated with an oxygen containing gas at elevated temperature to for a fuel gas in general and more particularly to an improved gas generator with a heat resistant housing and a reaction chamber which is centrally arranged therein which contains a catalytic charge, and which has an inlet opening for the reactants at one end and an outlet opening for the fuel gas at the other end.
Gas generators can serve, for instance, for catalytically converting hydrocarbon containing liquid fuels into a fuel gas which is better suited for the operation of internal combustion engines than the liquid fuel itself. For, in internal combustion engines fed with liquid fuel, the incomplete evaporation of the fuel and the non-uniform mixing with combustion air lead to incomplete combustion and to the emission of harmful substances. In addition, antiknock agents must be admixed to the fuel as a rule, which further increases the content of substances injurious to health in the exhaust gas. If internal combustion engines are operated with fuel gas, the objectionable pollution of the air otherwise produced can largely be avoided. This fuel gas can be generated in a reformed gas generator by partial catalytic oxidation of evaporated or atomized liquid fuel with an oxygen containing gas. This is followed by combustion of the fuel gas with further combustion air, in the internal combustion engine. Since this fuel gas (reformed gas) has a high octane number, the addition of antiknock agents is not needed.
So that such reformed gas generators can be used in motor vehicles, it is necessary that the design of the gas generator and all parts of the installation required for its operation, e.g., the heat exchanger for evaporating and heating up the materials used, be compact. Furthermore, reformed gas generators will be used on a large scale only if, through appropriate design of the gas generator, the costs for manufacture, installation and maintenance can be kept low.
A gas generator is disclosed in British Pat. No. 279,834, in which heavy oil is converted by partial thermal and catalytic combustion with air and, preferably, with the addition of water, into a fuel gas which is used to supply internal combustion engines. In this gas generator, a reaction chamber which is bounded by a cylindrical tube which is open on both sides is arranged in a housing closed-off by a cover plate. The tube has one edge fastened to the cover plate. The other edge, which protrudes into the interior of the housing, is bent toward the cylinder axis, and stacked perforated plates which act as the catalyst rest on it. A nozzle is also arranged at the cover plate for feeding in the reactants. The nozzle opens into a space of the reaction chamber which is free of catalyst. This space is situated in front of the plates and is provided with a refractory lining. There, sprayed in reactants are evaporated and in part converted thermally in the process. The vapors generated are subsequently conducted through the perforated plates and enter into the space between the reaction chamber and the housing. In this space a cup shaped partition, which is connected to the housing via spacers and which conducts the fuel gas leaving the reaction chamber at first along the outside wall of the chamber to the cover plate, is located. There, the fuel gas is deflected and is finally directed along the inside of the housing wall to a discharge stub attached at the center of the bottom of the housing. In the space in between, heat exchangers are further provided in order to warm up the reactants with the hot fuel gas before they are introduced into the reaction chamber. Thus, there is provided, for instance, for heating water, a tube which is run around the reaction chamber in helical turns and the cross section of which is substantially larger than the supply line leading to this tube, so that a large heat exchange area is obtained. Such a tube can also serve for heating the fuel. The tubes are fastened to the cover plate and lead outside the housing into the nozzle disposed at the cover plate. At the cover plate a starting device, is also provided. It opens into the reaction chamber and has an air inlet in which a fuel (e.g. coal or gasoline) can be ignited in order to conduct the hot fuel gas into the reaction chamber to heat up the catalyst.
The design of this known gas generator is relatively expensive, and its manufacture and maintenance would seem to involve high costs. In addition, because of its overall volume and its shape, it cannot be built into existing installations without problems.